Reorientational motion of pyridinium cation in pyridinium iodide across the phase transition (T-c = 247 K) temperature is studied using a high-resolution quasi-elastic neutron scattering (QENS) technique. A clear evidence of the order-disorder transition with respect to the pyridinium ion reorientation is observed. In the high-temperature phase the pyridinium ion is found to undergo a sixfold jump rotation around the axis perpendicular to its plane. Weak quasielastic broadening is observed below the phase transition temperature, at T = 240 K, indicating presence of residual disorder. Reorientational time and activation energy of rotation are also obtained in the high-temperature phase.